Tank gauge



Dec. 9, 1941. D. E, LARsoN- 2,265,736

TANK GAUGE Filed Dec. 30, 1940 2 Sheets-Sheefl 1 ft w i Zig' .2 y W# (lKQ /3 \\O 9, 1941. l D. E. LARsoN I TANK GAUGE Filed Dec. 30, 1940 75ma@ ZZ/ Jaffa/a www l Patented Dec. 9, 1941 TANK GAUGE Donald E. Larson,Chicago, Ill., assgnor to Chiy cago Bridge & Iron Company, a corporationof Illinois Application December 30, 1940, Serial No. 372,381

(Cl. Sii-126.6)

9 Claims.

This invention relates to improvements in tank gauge and more especiallysuch a device for measuring the height of liquid in a container. Theinvention is particularly applicable for use in connection with oilstorage tanks and more especially closed tanks. similar volatilehydrocarbon oils are frequently kept in closed containers underpressure. My'device can be used with such a container and operated atall times without releasing the pressure or venting the gas from thecontainer.

`My improved device is also useful in connection with a container havinga iiexible roof. The device is mounted on the roof and vertical movementof the latter does not affect the gauging operation.

Other features and advantages of my invention will appear` more fully asI proceed with my specification.

In that form of device embodying the features of my inventionillustrated in the accompanying drawings, Fig. 1 is a view in frontelevation; Fig. 2 is a view in side elevation; Fig. 3`is a verticalsectional view of the reeling mechanism; and Fig. 4' is a view taken asindicated by the line 4 of Fig. 3.

As shown in the drawings, I mayindicate a roof or top of a tank such asan oil storage tank. II indicates in general a casing suitably mountedon the roof in any convenient manner.

The upper part of the casing as indicated by I2 contains reeling meansfor an elongated ilexible element such as a steel tape carrying a Weightor bob on the lower end. By means of the reeling mechanism the lower endof the tape may be raised or lowered to raise or lower the weight. As

`so far described, the gauging mechanism is conventional. It has beenthe practice t0 lower the weight until it engages the bottom-of the tankand then pull up the tape and note the height of the wet portion. Thetape may be suitably coated so that the line between the -Wet and drypor- -tions can be easily noted. 'I'his is all old in the art.

Heretofore, difliculty has been encountered in noting just when theweight engages the bottom of the tank. Unless the weight is very heavy,the differences in tension caused by the Weight strik-- ing the bottomwas not readily ascertainable at the top. The principal feature of myinvention is the provision of automatic locking means for the reelingmechanism so that when the Weight strikes the bottom the reeling meanswill be automatlcally locked. This prevents the lowering of additionaltape into the liquid that obviously For example, gasoline and would givea false `indication of the height of the liquid in the tank.

In general, my invention is accomplished by providing locking means forthe reeling mechanism which is normally in locking position andproviding in conjunction therewith means operated through the exibleelement by the weight when suspended thereby forholding the lockingmeans in release position. When the weight engages the bottom of thetank it 4no longer holds the locking means in release position and said'locking means thereby movesv automatically to locking position to holdthereeling means sta- I3 indicates a reel or drum mounted on the shaftI4 operated by the 4handle I5. Where the f shaft projects from thecasing I2 suitable packing is provided as indicated by I6. I1 indicatesa' steel tape wound on ythe drum I3 carrying on its lower vend the bobor weight I8 adapted to engage the bottom I9 of the tank when in itslowermost position.

The lower part of the casing I I is provided with a chamber 20containing closure means (not shown) adapted to close the casing IIagainst escape of gas from the tank' and yet permit the tape I1 toremain thereon. Such closure-means is well known in the art and forms nopart of the present invention and consequently need not be shown here indetail. It is ordinarily provided to permit opening of the window-2| inthe casing II, if desired, without permitting escape of gas therefrom. A

'I'he dru I3 at one side carries the ratchet wheel I3a, he teeth ofwhich are adapted to be engaged by the claw 22 on the end of the arm 23pivoted on the stationary pin 24. The arm 2l.

.is provided with a rearwardly extending portion 23a adapted to beengaged by the arm 25 pivoted at 2Q and carrying the Wheel 21 on itsfree end over which the tape I1 passes. The arm 25 is provided with anextension 25a in the nature of a bellcrank connected to lthe tensionspring- 28 which tends to move the arm 25 into the dotted position shownin Fig. 3; that is, with the wheel 2'l raised. When in this position theclaw 22 on the small lever 23 falls into locking position or engagementwith the teeth on the ratchet wheel normally pressed member 30, carriedby the extension casing 3l on 30 is stationary in the casing. 3 I iscarried on the crank 32 pivotally mounted to the member 33 on the shaftI4. Normally the members 28 and 30 are in frictional engagement toprevent rotation of the shaft. To release these the crank 32 is swung onits pivot 34 to press the member 29 inwardly against the' tension of thespring 35 to release the clutch to permit ro-y tation of the shaft. Uponrelease of -the handle 1 I5 the clutch is automatically engaged.

In operation, before the gauging is commenced, the parts are in theposition shown by the solid lines in Fig. 3. In this position theweight' is suspended by the tapeV I1 and is heavy enough Qto extend thespring 28 so that the arm 25 is `engaging the end 23a of the lockinglever 23 to @hold the same in released position. The tape is `thenunreeled slowly until the bob I8 engages i the bottom I9 of the tank. Asthe weight of the bob isthen removed from the tape I1 further unreelingcauses the spring 28 to raise the arm` `25. This permits the claw 22 todrop into engagement with one of the teeth on the wheel I3a `and lockthe reeling mechanism against further unwinding. The tape is then woundup and the height of liquid thereon noted throughv the.

window 2|.

It is to be noted further that the device automatically locks the reeland simultaneously insures application of tension to the tape I1 throughthe action of the spring 28. This tension is not of an exactpredetermined value, but it is substantially constant through generallimitsand is suicient for ordinary gauge indications.

`If the top of the tank moves upwardly a small amount after the reel hasbeen locked, this small movement is accommodated by action of the spring28 to maintain a substantially constant -tape tension. If greater upwardmovement at the `top of the tank occurs, then the ratchet 22 unllocksfor one or more teeth of the ratchet wheel, lthus automaticallymaintaining tension and in- I `surng that the weight remains in contactwith the bottom. Should the top of the tank move `downwardly from itsinitial position, then this movement is accommodated by the relative up-`ward movement of the reel 21 under the action `of spring 28.

, The action of the spring 28' in conjunction `with theratchet 22 is toautomatically apply the `casing II around the shaft I4. The member Thehandle I A 2 v 2,265,736 l when the handle I5 is released. 29 indicatesa 1 clutch member slidably. but non-rotatably mounted on the shaft I4 ana A r into engagement with the cooperating clutch Changea'therefre, inthe construction and arrangement may be made without departing fromv thespirit and scope of the invention as disclosed in the appended claims,in which it is my intention to claim all novelty inherent in myinvention as broadly as permissible, in' view of the prior art.

What I claim as new and desire to secure by Letters Patent is:

1. A tank gauge,including: an elongated ilex-A ible element adapted toextend down into the tank; reeling means adjacent the top of the tank toraise'or lower the lower end of the flexible element; a weight carriedby the lowerv end of the flexible element; locking means for the reelingmeans; means operated through the flexible element by the weight whensuspended thereby for holding the locking means in release tension onthe tape after the weight has engaged l the bottom of the tank, and tomaintain tension y irrespective of movement of the top of the tank.

`In other words, the action of the spring 28 in commotion with theratchet' 22 automatically `applies tension on the tape after the weighthas v engaged the-bottom of the tank and maintains tension irrespectiveof the movement of the top of the tank. It is generally desirable toapply a more or less uniform tension to the ltape during the taking ofreadings in order to prevent inaccuracies. In other words, the spring 28acts as a biasing means in conjunction with the re-r ;leasable lockingmeans for automatically apply- Aingsubstantially uniform tension to thetape `when the weight rests on the bottom of thetank.

position; and means for imposing a tension on the flexible elementv(insuiiicient to" lift the weight) when the locking means is in lockedposition.

2. A tank gauge, including: an elongated ex. ible element adapted toextend down into the tank; reeling means adjacent the top of the tank toraise or lower the lower end of the flexible element; a weight carriedby the lower end of the flexible element; locking means for the -reelingmeans; means urging the locking means 4. Apparatus as claimed in claim 2in whichv the means operated by the weight includes a .movable membercarrying a wheel over which the exible element lies.

5. Apparatus as claimed in claim 1 with a handle for operating thereeling means and clutch mechanism for holding the reeling means againstrotation, said clutch mechanism adapted to be released by movement ofthe handle to operative position.

6. Apparatus as claimed in claim 2 with a handle for operating thereeling means and clutch mechanism for holding the reeling means againstrotation, said clutch mechanism adapted to be released by movement ofthe handle to operative position.

7. In combination with a tank having a. vertically movable top, a tankgauge, including: an elongated flexible element adapted to extend downin to the tank; reeling means adjacent the top of the tank to raise orlower the lower end of the flexible eiment; a weight carried by thelower end of the flexible element; and means for maintainingsubstantially uniform tension on the elongated exible element after theweight touches the bottom of the tank, regardless of vertical movementof the topvof the tank within limits.

8. In combination with a tank having'a vertically movable top, a tankgauge, including: an elongated exible element adapted to extend v downinto the tank; reeling means adjacent the While I have shown anddescribed certain embodiments of my invention, it is to be understoodthat it is capable of many modifications.

top of the tank to raise or lower the lower end of the exible element; aweight carried by the lower end ofthe flexible element; locking meansfor the reeling means normally in locking position; and means forautomatically maintaining substantially uniform tension on the elongatedflexible element after the weighty touches the tank; a weight carried bythe lower en d of the flexible element;4 Vreeling means normally freefor rotation when the weightis suspended by said elongated exibleelement; llocking means for the reeling means; means releasable bydecreased tension on said elongated flexible element to release saidlocking means and lock said reeling means, said releasable meansoperating to impose a tension on the flexible element (insucient to liftthe Weight). when the locking 10 .means is in locking position.

DONALD E. mason.

